85 minutes of panic sweeps London's Oxford Circus

London: Panic swept London's popular shopping strip on Friday night as reports of "shots fired" at Oxford Circus underground station briefly brought parts of the city to a standstill.

British Transport Police responded to "reports of shots fired" at the tube station at 4.37pm (3.37am AEDT). Six minutes later the London fire brigade was called.

Armed police swarmed the scene within one minute of receiving the first call.

Scotland Yard said they responded "as if the incident was terrorism." But terror did not transpire, they found no evidence of gunshots, and by 6.02pm, the station was reopened.

But in the 85 minutes between, Londoners took to their social media accounts to share their panic as they watched a human stampede emerge from the underground.

For those underground, it was, initially a different story.

Annabel Samantha, a 22-year old fashion student, was on the Central line platform at Oxford Circus where a fight broke out, the apparent cause of the chaos.

"The platform I was stood at broke into a massive fight which created a bit of a scene, around 50-100 people gathering around something which I at first thought was someone on the floor," she told Fairfax Media.

"Lots of people were distressed and that upset a lot of kids who were with the adults involved, and they started running off creating more shouting and crying.

"The security had to inform the transport police, which then broke into an emergency evacuation via the speakers. This created even more upset and drama and then a stampede of people trying to leave," she said.

Police said the only person injured on Friday evening was hurt as a result of the human stampede.

Jordan Vadnais, 35, was arriving at Oxford Circus from Victoria after a holiday in Lisbon with his husband Ryan Hartigan when they heard the evacuation alert.

"As we were leaving the train we heard the alert that everyone needed to evacuate the station. At that point it seemed to be orderly," he said.

"But that changed when they reached ground level and heard screams behind them.

"The crowd just pushed and it was as stampede."

Witnesses would later say it was a fight on a platform that sparked the scare, but the photos and videos of commuters rushing from Oxford Circus, one of the underground's busiest stations, contributed to the sense of panic.

And for Jordan and Ryan, without having seen the fight on the platform, they too feared another crude vehicle ramming attack targeting pre-Christmas shoppers.

"What went through my mind immediately was 'It's Black Friday on Oxford Circus in a city that's had incidents', and as I ran I was too terrified to look back because I thought I would see a car heading towards us," he said.

Without any evidence, one media outlet reported a lorry or truck was at the centre of the incident.

The chaos further spread when the reports of gunshots emerged several blocks down Oxford Street at Selfridges.

Singer Olly Murs was shopping in the high-end department store at 5pm when he urged his nearly 8 million Twitter followers to get out, if any were inside.

"F--- everyone get out of @Selfridges now gun shots!! I'm inside," he tweeted.

"Really not sure what's happened! I'm in the back office ... but people screaming and running towards exits!"

"Evacuating store now!!! F--- heart is pounding."

Within half an hour he followed up: "Being told no shots in Selfridges! Have no idea, the whole store went crazy."

Selfridges said it was evacuated "as a precautionary measure."

"We have been working with Metropolitan Police and can confirm that were no reported incidents in store," the store said.

Murs was being hammered on Twitter for spreading false rumours.

But the jumpiness the Black Friday incident sparked is understandable.

Londoners have become accustomed to terror attacks - indeed they expect them - having been targeted on Westminister Bridge, the parliament, on London Bridge and at Borough Market, and most recently on the tube at Parson's Green.

The deadliest attack was in Manchester where Ariana Grande fans were targeted leaving her concert at the arena.

But just as the city is jumpy, it is also characteristically good at getting on with it.

At 5.45pm, Southwark Station, four stops from Bond Street station, told commuters entering the station via its noticeboard that Bond Street and Oxford Circus were closed.

By the time those same commuters reached the platform both stations had reopened. The noticeboard was devoid of any mention of closures by 5.49pm.

The live news radio and television channels dropped their live coverage of the incident and returned to reporting on Theresa May's visit to Brussels to discuss Brexit negotiations.

Police on Oxford Street dropped the cordon and deployed extra officers to the west end, and while nobody caught up in the panic is likely to forget it quickly, London got on with its Friday night.

Keep Calm and Carry On.

British Transport Police later said they wanted to speak to two men believed involved in the fight that started the incident. It posted CCTV images of the men, saying they also wanted to speak to witnesses.

In a statement it said officers believed an altercation erupted between two men on the platform. "They would now like to speak to these two people in the CCTV images, who they believe may have information about the incident and the circumstances around the incident." It also urged witnesses to come forward with any information, "big or small".

We are releasing CCTV images of two men we would like to speak with following the incident at Oxford Circus earlier today.